How Do Sunscreens Work?
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How Do Sunscreens Work?

Sunscreens are designed to protect the skin from the ultraviolet rays of the sun. The damaging UV rays are called UVA and UVB. You may have seen people who spend a lot of time out in the sun without any UV protection. Their skin gets wrinkly and weathered looking. The skin of a person who doesn’t use protective sun screen or shield themselves from the sun’s rays is more susceptible to getting melanoma and other kinds of skin cancers.

What is the difference between UVA and UVB rays?

UVA rays are the ones that penetrate deeper into the skin. They have longer wavelengths.  UVB rays have shorter wave lengths and don’t penetrate as far into the skin. We are most vulnerable to the UVB rays because they aren’t readily absorbed by the ozone level in the atmosphere.

Why do we need to use sunscreen?

You may justify that you don’t need sunscreen if you wear a hat and long sleeves. This may be true, but if the fabric of your hat and clothing is such that the sun’s rays can filter through your clothing, you can still get skin damage from the UV rays of the sun. You need to wear sunscreen if you are going to be out in the sun for at least 15 minutes. All it takes is 15 minutes for your skin to start reacting to the sun. The UV rays of the sun begin to react with the DNA of your skin.

How sunscreens work

Sunscreens work in different ways. Some of them work by absorbing the UV rays of the sun, while others reflect and scatter the rays. You might wonder if all sunscreens do the same things. They don’t. There is a difference in sunscreens. Each sunscreen product has a SPF (sun protection factor) number.

Do the higher SPF numbers mean the product is stronger than the lower numbers?

The higher the number is on the product the longer your protection will last. It doesn’t actually increase the amount of protection, but it does increase the time you are protected. For instance, a sunscreen that has an SPF of 20 will give you 20 times more the protection than if you hadn’t used sunscreen at all. Likewise, an SPF of 30 will give you 30 times more protection than if you weren’t wearing anything. However, it does not give you stronger protection. It just gives you longer protection.

Protection from sunscreens

A person with fair skin might begin to burn in 10 minutes. So if you are wearing a sunscreen with an SPF of 20 you will be protected for 200 minutes. The math is like this: 10 x 20 minutes = 200 minutes of protection. If you normally can stay in the sun 20 minutes before beginning to burn the math would be even more dramatic with a sunscreen with an SPF of 20. The math would be 20 x 20 minutes = 400 minutes of protection. I have very fair skin and will start burning within 10 minutes, so I would follow the first example.

Be careful with your skin

You should use common sense when wearing sunscreens. The results you get from a sunscreen may differ from what the label says you can expect from a sunscreen.  The difference lies in that the testing is done in a laboratory. You may apply the sunscreen and go into the water and come out and begin to burn. This is because the sunscreen has been washed off by going into the water. You should dry yourself off and reapply the sunscreen as necessary.

You will need to reapply the product at intervals while you are out in the sun.  For instance, if you are fair skinned and you are wearing an SPF of 15, you may need to reapply the product every couple of hours. Theoretically, if you normally start burning in 10 minutes you will have 150 minutes of protection. However, use common sense. It would be good to reapply the product once every hour or two to protect the skin from burning and to protect the skin from the threat of skin cancer.


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Comments (3)

Very Informative Charlene!

well done